The use of breathing devices in non-breathable atmospheres is well known. In some instances, self-contained breathing apparatus (“SCBA”) may be utilized to provide breathing air to the user. In other situations, a hose-line respirator connected to a remote air source is utilized. The hose-line respirator may be used in situations where workers are required to work for a long period of time in an atmosphere containing a hazardous substance. Also, the hose line respirator may be used if there is not enough room for a larger tank to be carried into the work area. For the above reasons and others, it is sometimes preferable to use a hose-line connected between the user's breathing mask and a remote large source of breathable gas.
When a hose-line respirator attached to a remote supply of breathing gas is utilized, there is a need for an emergency escape respirator. The need arises because the remote breathing gas supply may fail. For example, the hose line may become uncoupled from the breathing gas source. Also, the hose may be accidentally damaged or even severed between the breathing mask and the breathing gas supply.
Some escape systems require at least some conscious participation by the user or other person, a requirement which may not be feasible in a sudden emergency situation where the user is restrained by being trapped or otherwise disoriented, unconscious or so stricken as to be unable to think or act appropriately. For example, a small supply of compressed air is carried on the person and is connected by a Tee into the air supply line. If the air supply through the hose line should fail, the worker is instructed to open the valve of his reserve air supply and immediately leave the area. In order to make such a device practical, the air from the reserve cylinder is first run through a regulator to reduce its pressure. A check valve is also incorporated to prevent the air from the emergency supply traveling down the hose towards the original air supply.
Accordingly, there is a need for a transfer regulator capable of automatically switching the breathing gas supply from the hose-line to a portable emergency tank when the flow of breathing gas through the hose-line is disrupted. There is also a need for a system that automatically resets itself when the supply of breathing gas from the remote source is restored.